A conventional ink cartridge houses an ink bag. A valve is attached to the ink bag for controlling the supply of ink to a recording device. When the user mounts the ink cartridge into the recording device, an ink supply needle provided in the recording device opens the ink bag valve, allowing ink in the ink bag to be supplied to the recording device through the ink supply needle.
There is another conventional inkjet printer, in which a subsidiary tank is provided between a main tank and an inkjet head. The subsidiary tank is for separating air from ink and for generating a desired pressure head difference between the inkjet head and the subsidiary tank.